Example URL:
https://www.google.co.in/search?q=wallpaper+for+infinity+display&client=ms-android-micromax&prmd=inv&source=lnms&tbm=isch&sa=X&ved=0ahUKEwi_tdDA7KfbAhVKuI8KHXJWDkAQ_AUIESgB&biw=360&bih=559#imgrc=z0VtEPdxBC1QCM%3A

Steps to reproduce the problem:
1. Go to the specified url
2. Then you can see a wallpaper image
3. Then long press on the image
4.then select the 'download image'
Option
5.then a pop up menu will arise as below 
"Do you want to download images.jpeg again?"

If the pop up menu doesn't arise and download the image normally, you again try to download the same image.Then you can definitely see the pop up dialogue as mentioned above.
6.after pressing OK and proceeds the download it doesn't start the download operation.

What is the expected behavior?

What went wrong?
Note:in Google images images are downloaded with some common general names like download.jpg,unnamed.png,images.jpeg etc. 
 this problem is only for 'images.jpeg' labelled images.

Did this work before? No 

Chrome version: 66.0.3359.158  Channel: stable
OS Version: 5.1.1
Flash Version: 

Another issue is also associating to this issue.That is the unwanted dialogue box creation while every image download attempt as "Do you want to download google_generalname.extension?" google_generalname can be unnamed,images,download etc.Due to this Images lost their original names to these general names.hence the dialogue box creation.